A state of the art review on optimal practices to prevent,recognize, and manage complications associated with intravascular devices in the critically ill

Intravascular catheters are inserted into almost all critically ill patients. This review provides up-to-date insight into available knowledge on epidemiology and diagnosis of complications of central vein and arterial catheters in ICU. It discusses the optimal therapy of catheter-related infections and thrombosis. Prevention of complications is a multidisciplinary task that combines both improvement of the process of care and introduction of new technologies. We emphasize the main component of the prevention strategies that should be used in critical care and propose areas of future investigation in this field.     

Demographic characteristics and prevalence of serologic markers among donors who use the confidential unit exclusion process: the Retrovirus Epidemiology Donor Study

BACKGROUND: Most blood centers utilize a confidential unit exclusion (CUE) process, intended to reduce the risk of transfusion-associated infectious diseases by allowing high-risk donors confidentially to exclude their blood from use for transfusion. The effectiveness of this method remains controversial. STUDY DESIGN AND METHODS: Confirmatory or supplemental test results for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus, as well as hepatitis B surface antigen and syphilis and screening test results for antibodies to hepatitis B core (antigen) and alanine aminotransferase levels were obtained for approximately 1.8 million units donated during 1991 and 1992 at five blood centers within the United States. The prevalences of these infectious disease markers in units that the donors confidentially excluded (CUE+) and units that the donors did not exclude (CUE-) were calculated and examined within demographic subgroups. RESULTS: Units that were CUE+ were 8 to 41 times more likely to be seropositive for antibodies to human immunodeficiency virus and hepatitis C virus, hepatitis B surface antigen, and syphilis and three to four times more likely to react for antibody to hepatitis B core (antigen) or to have elevated alanine aminotransferase levels than units that were CUE- (p < 0.001). The positive predictive value of CUE (the percentage of CUE+ units that were confirmed seropositive for any marker) was 3.5 percent, and the sensitivity of CUE (the percentage of confirmed-seropositive units that were CUE+) was 2.3 percent. CONCLUSION: The current CUE process has low sensitivity and apparently low positive predictive value, and in many cases, it appeared that donors misunderstood it. Yet, CUE was not a “random process,” as CUE+ units were more likely to be seropositive for any infectious disease marker than CUE- units. This suggests that efforts to improve the CUE system may be warranted. As risk factors for transfusion-transmitted infection become more difficult to identify by history-based screening, however, such efforts may have limited effect.     

Steatotic livers are susceptible to normothermic ischemia-reperfusion injury from mitochondrial Complex-I dysfunction

AIM: To assess the effects of ischemic preconditioning (IPC, 10-min ischemia/10-min reperfusion) on steatotic liver mitochondrial function after normothermic ischemia-reperfusion injury (IRI). METHODS: Sixty male Sprague-Dawley rats were fed 8-wk with either control chow or high-fat/high-sucrose diet inducing > 60% mixed steatosis. Three groups (n = 10/group) for each dietary state were tested: (1) the IRI group underwent 60 min partial hepatic ischemia and 4 h reperfusion; (2) the IPC group underwent IPC prior to same standard IRI; and (3) sham underwent the same surgery without IRI or IPC. Hepatic mitochondrial function was analyzed by oxygraphs. Mitochondrial Complex-I, Complex-II enzyme activity, serum alanine aminotransferase (ALT), and histological injury were measured. RESULTS: Steatotic-IRI livers had a greater increase in ALT (2476 ± 166 vs 1457 ± 103 IU/L, P < 0.01) and histological injury following IRI compared to the lean liver group. Steatotic-IRI demonstrated lower Complex-I activity at baseline [78.4 ± 2.5 vs 116.4 ± 6.0 nmol/(min.mg protein), P < 0.001] and following IRI [28.0 ± 6.2 vs 104.3 ± 12.6 nmol/(min.mg protein), P < 0.001]. Steatotic-IRI also demonstrated impaired Complex-I function post-IRI compared to the lean liver IRI group. Complex-II activity was unaffected by hepatic steatosis or IRI. Lean liver mitochondrial function was unchanged following IRI. IPC normalized ALT and histological injury in steatotic livers but had no effect on overall steatotic liver mitochondrial function or individual mitochondrial complex enzyme activities. CONCLUSION: Warm IRI impairs steatotic liver Complex-I activity and function. The protective effects of IPC in steatotic livers may not be mediated through mitochondria.     

Aspirin responsive platelet thrombophilia in essential thrombocythemia and polycythemia vera

Essential thrombocythemia (ET) and polycythemia vera (PV) frequently present with erythromelalgia and acrocyanotic complications, migraine-like microvascular cerebral and ocular transient ischemic attacks (MIAs) and/or acute coronary disease. The spectrum of MIAs in ET range from poorly localized symptoms of transient unsteadiness, dysarthria and scintillating scotoma to focal symptoms of transient monocular blindness, transient mono- or hemiparesis or both. The attacks all have a sudden onset, occur sequentially rather than simultaneously, last for a few seconds to several minutes and are usually associated with a dull, pulsatile or migraine-like headache. Increased hematocrit and blood viscosity in PV patients aggravate the microvascular ischemic syndrome of thrombocythemia to major arterial and venous thrombotic complications. Phlebotomy to correct hematocrit to normal in PV significantly reduces major arterial and venous thrombotic complications, but fails to prevent the platelet-mediated erythromelalgia and MIAs. Complete long-term relief of the erythromelalgic microvascular disturbances, MIAs and major thrombosis in ET and PV patients can be obtained with low dose aspirin and platelet reduction to normal, but not with anticoagulation. Skin punch biopsies from the erythromelalgic area show fibromuscular intimal proliferation of arterioles complicated by occlusive platelet-rich thrombi leading to acrocyanotic ischemia. Symptomatic ET patients with erythromelalgic microvascular disturbances have shortened platelet survival, increased platelet activation markers β-thromboglobulin (β-TG), platelet factor 4 (PF4) and thrombomoduline (TM), increased urinary thromboxane B2 (TXB2) excretion, and no activation of the coagulation markers thrombin fragments F1+2 and fibrin degradation products. Inhibition of platelet cyclooxygenase (COX1) by aspirin is followed by the disappearance and no recurrence of microvascular disturbances, increase in platelet number, correction of the shortened platelet survival times to normal, and reduction of increased plasma levels of β-TG, PF4, TM and urinary TXB2 excretion to normal. These results indicate that platelet-mediated fibromuscular intimal proliferation and platelet-rich thrombi in the peripheral, cerebral and coronary end-arterial microvasculature are responsible for the erythromelalgic ischemic complications, MIAs and splanchnic vein thrombosis. Baseline platelet P-selectin levels and arachidonic acid induced COX1 mediated platelet activation showed a highly significant increase of platelet P-selectin expression (not seen in ADP and collagen stimulated platelets), which was significantly higher in JAK2^V617F mutated compared to JAK2 wild type ET.     

Alcoholic povidone-iodine to prevent central venous catheter colonization: A randomized unit-crossover study

OBJECTIVE: To compare effectiveness in preventing central venous catheter colonization and infection of two protocols of cutaneous antisepsis using povidone-iodine solution in combination with ethanol or water. DESIGN: Randomized trial. SETTING: Medical intensive care department in a university hospital. PATIENTS: Consecutive patients requiring central venous catheter in two similar 11-bed units from January 1, 2001, to January 1, 2002. INTERVENTIONS: Alcoholic povidone-iodine solution protocol was randomly assigned to one of two units when the study began. Every 3 months the alcoholic protocol was switched from one unit to the other. Depending on the unit and the time the patient was admitted, catheters were inserted and cared for with 10% aqueous povidone-iodine solution or 5% povidone-iodine solution 70% ethanol-based combination. MEASUREMENTS AND MAIN RESULTS: Rates of catheter colonization, catheter-related bacteremia, and catheter-related infection were compared in the two protocols; 223 catheters were included in an intent-to-treat analysis. The incidence of catheter colonization was significantly lower in the alcoholic povidone-iodine solution protocol than in the aqueous povidone-iodine solution protocol (relative risk, 0.38; 95% confidence interval, 0.22-0.65, p <.001), and so was the incidence of catheter-related infection (relative risk, 0.34; 95% confidence interval, 0.13-0.91, p <.04). Catheter-related bacteremia were similar in both protocols. After adjusting for other risk factors, time to central venous catheter colonization was significantly longer in the alcoholic solution (adjusted hazards ratio, 0.3; 95% confidence interval, 0.2-0.6, p <.001). Based on a subgroup of 114 patients (57 in each protocol), analysis of 57 pairs of central venous catheters matched for age, duration, and site of insertion found similar results regarding the superiority of alcoholic povidone-iodine solution in preventing central venous catheter colonization and infection. CONCLUSIONS: The use of alcoholic povidone-iodine for skin disinfection reduced the incidence of catheter colonization and related infection compared with aqueous 10% povidone-iodine disinfection in an adult intensive care unit.     

Amplatzer封堵器的生物学性能及经导管介入治疗房间隔缺损

目的:评价经导管置入Amplatzer封堵器治疗继发孔房间隔缺损的治疗效果。方法:①选择2002-08/2006-04在兰州市第一人民医院心外科住院的继发孔型房间隔缺损65例,男26例,女39例;平均年龄(18±8)岁;平均房间隔缺损直径(19.3±7.2)mm。纳入患者对手术方案知情同意。②手术所用封堵器为美国公司的Amplatzer房间隔缺损封堵器,是一种新型的适于关闭二孔型房间隔缺损的装置,它由具有自膨胀性的双盘及连接双盘的腰部三部分组成。双盘状结构恢复记忆形状后可以稳定封堵房间隔缺损的边缘部分,降低残余分流的发生率。③根据选择封堵器大小的方式(即球囊测量或经胸超声心动图直接观察)将患者分为球囊测量组38例和经胸超声心动图测量组27例。均在透视及经胸超声心动图监视下经导管置入Amplatzer封堵器封堵房间隔缺损。同时测量患者缺损扩张直径、封堵器大小,记录X射线透视时间和手术时间。④术后即刻、24h、3个月及1年分别行经胸超声心动图、心电图及X射线检查评价治疗效果。⑤超声心动图显示完全无分流为无分流;残余分流血流宽度≤1mm为微量分流;血流宽度1.0～2.0mm为少量残余分流;血流宽度2～4mm为中量残余分流;血流宽度>4mm为大量残余分流。⑥组间计量资料差异比较采用两个独立样本t检验,组间手术效果比较采用两个独立样本的等级资料秩和检验。结果:①技术成功率:65例房间隔缺损患者,64例封堵器置入成功,技术成功率为98%。②选择封堵器直径:球囊测量组缺损扩张直径为(20.4±6.1)mm,选择的封堵器直径为(21.6±5.7)mm,与经胸超声心动图测量组相近[(22.5±4.3),(25.1±4.9)mm,P>0.05]。③术后残余分流情况:术后即刻经胸超声心动图显示,球囊测量组35例完全无分流,经胸超声心动图组有23例,差异不明显(P>0.05);术后24h,球囊测量组36例完全无分流,经胸超声心动图组有24例,差异不明显(P>0.05);术后3个月,球囊测量组37例完全无分流,经胸超声心动图组有25例,差异不明显(P>0.05);术后1年完成随访的52例患者均未见封堵器移位及房间隔缺损再通。④X射线平片检查:全部显示肺血减少,右心房、室缩小。结论:封堵器直径比球囊测量的房间隔缺损扩张直径大1.0～2.0mm,比超声心动图测量的大2～6mm封堵效果好,成功率高。